The unipolar barrier is a new approach for control of dark currents in infrared photodetectors. First demonstrated in the
nBn detector and then in the unipolar barrier photodiode, unipolar barriers have been shown to block surface leakage
current. Unipolar barriers can also be implemented to filter out dark current components such as Shockley-Read-Hall
current, direct band-to-band tunneling and trap-assisted tunneling, but are not useful for blocking diffusion currents.
Current density-voltage characteristics of molecular-beam-epitaxy-grown InAs based unipolar barrier photodiodes are
presented and analyzed, showing effective limiting of noise current mechanisms for different unipolar barrier photodiode
architectures. RoA data shows near Auger-limited device performance and RoA values in excess of 1x107 Ω-cm2.